The sieve spec seems to be geared largely at mailbox level filtering, and
sure for a mailbox level filter we should only allow access to 1 recipient,
but for domain or server level filtering perhaps there is application for
the envelope test having access to all the envelope recipients?
Perhaps, but it is currently forbidden.
There are
several such "tweaks" that you need to do when adapting Sieve to the domain
or server level. For example "fileinto" is really a "copy to directory" not
a "fileinto mail folder".
Having implemented this, my interpretation is that fileinto isn't a
particularly meaningful action for a higher level sieve to do.
Is it really that harmful to put some comment in this spec to say:
A mailbox level implementation MUST ensure that the test for envelope "to"
only reflects the delivery to the current users, but a domain or server
level implementation MAY allow the envelope test to reflect the "to" or
"from" headers to the relevant domain or server.
Yes, since it directs contradicts the base specification.
Sieve isn't only useful at the mailbox level after all, it's great as a
server level spam filter too!
Sure, but it is very debatable how much value access to envelope addresses
adds to such uses.
Ned